According to the World Health Organization (WHO), urban outdoor air pollution is estimated to cause 1.3 million deaths worldwide per year. Those living in middle-income countries disproportionately experience this burden. The American Heart Association states that air pollutants contribute measurably and significantly to both acute and chronic cardiovascular and pulmonary disease. Air pollutants are comprised of particulate matter and other gaseous chemicals that can be harmful to a person's health when inhaled. The outdoor air pollution in many cities around the world far exceeds the WHO recommended levels for health, containing an unsafe amount of particulate matter and potentially toxic gasses because of the emissions generated by the heightened industrial activity and vehicle emissions in and around those cities.
To protect themselves from breathing these harmful pollutants, some people wear respirator type masks while outdoors. These masks can either be simple cloth scarves that are wrapped around the user's nose and mouth, or more advanced masks such as an N95 disposable particulate respirator.
Although respirator masks are in common use, they have a number of disadvantages. They are visually unsightly and feel restrictive because they tend to cover a major portion of the user's face, usually extending from the lower chin, over the mouth and nose and ending just under the user's eyes. Wearing a mask carries a stigma as other people may assume that the user is ill and attempt to avoid contact with them. Without a proper fitting, it is difficult to achieve a tight seal around the user's face with facemask respirators (and nearly impossible to achieve a proper seal if the user has facial hair, facial deformities or sensitive skin), thus allowing the user to inhale more unfiltered air and minimizing the effectiveness of the respirator. When these masks are held on by utilizing straps that wrap around the user's head, the straps tend to disturb a person's hair and also contribute to the unfavorable visual impression. For these reasons and others, many people elect not to wear a protective face mask even though, due to poor air quality, there may be a serious risk to their health from breathing the ambient air in the area where they live or work.
A number of attempts have been made to address the issues with facemask respirators described above. However, these non-mask respirators have their own drawbacks. For example, U.S. Pat. No. 4,915,105 shows a respiratory apparatus with a nostril intake manifold connected to two hoses that surround the user's head and join to one extension tube leading to a filter box attached to the user's waist. U.S. Pat. No. 6,971,386 shows a device with a mouthpiece and check valves leading to two tubes that encircle the user's head with the filter cartridge placed behind the user's head on the upper back or neck. The device balances on the user's shoulders and is held on by biting the mouthpiece. Each of the above devices wrap around the user's head and are difficult to manage and unwieldy to use in daily activities. They are also visually obtrusive and unattractive. Further, the distance of the filter from the breath intake orifice, particularly for U.S. Pat. No. 4,915,105 and similar devices, creates a greater drag on air flow increasing the effort necessary to inhale if the device is not powered.
U.S. Pat. Nos. 5,782,234; 5,771,885 and 7,025,060 show more compact respirators where the device is held in the user's mouth and gripped by his or her teeth. The filter is located directly in front of the user's mouth and employs air flow check valves. While these mouth-held respirators avoid the larger size and unwieldiness of the previously described respirators, these mouth-held respirators have other issues. As these respirators are held in solely by force of the teeth, the respirator will fall out if the user tries to speak without removing it entirely. If the respirator is used for extended periods, the user's jaw could tire from supporting the entire weight of the device. The position of the filter protruding from the user's mouth also gives these respirators a strange appearance.
Furthermore, for nostril plug type filters (see, e.g., U.S. Pat. Nos. 7,918,225 and 6,962,156), the entire filter mechanism is inserted into the user's nostrils. These are single-use devices that must be replaced after each use, and the amount of filtration material that can be used is limited to a size that fits inside a human nostril. In addition, these nostril plug type filters do not accommodate persons who prefer to breathe through their mouth, which is often necessary when engaging in strenuous exercise.
Thus, the need exists for a personal air filter designed to minimize or eliminate one or more of these problems and to provide greater comfort and ease of use to the user, thereby increasing the likelihood that a person will wear the device and realize its health benefits.